Entanglement quantification through local observable correlations

Abstract

We present a significantly improved scheme of entanglement detection inspired by local uncertainty relations for a system consisting of two qubits. Developing the underlying idea of local uncertainty relations, namely correlations, we demonstrate that it's possible to define a measure which is invariant under local unitary transformations and which is based only on local measurements. It is quite simple to implement experimentally and it allows entanglement quantification in a certain range for mixed states and exactly for pure states, without first obtaining full knowledge (e.g. through tomography) of the state.

5 pages, 3 figures, revised version with new proof and replaced figures

References in corpus (1)

• Nonlinear entanglement witnesses

Cited by in corpus (10)

• Lower bounds on concurrence and separability conditions
• Optimal entanglement witnesses based on local orthogonal observables
• Further results on entanglement detection and quantification from the correlation matrix criterion
• Complementarity and correlations
• Quantifying geometric measure of entanglement by mean value of spin and spin correlations for pure and mixed states
• High-dimensional entanglement certification
• Convex politopes and quantum separability
• Reliable experimental quantification of bipartite entanglement without reference frames
• Inferred-variance uncertainty relations in the presence of quantum entanglement
• Qubit-qunit decomposition of quantum channel